ARS | Publication request: Differential expression of trichomes on the leaves of upland cotton (Gossypium hirsutum L)

Submitted to: Journal of Cotton Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: June 7, 2011
Publication Date: February 8, 2012
Citation: Turley, R.B., Vaughn, K.C. 2012. Differential expression of trichomes on the leaves of upland cotton (Gossypium hirsutum L). Journal of Cotton Science. 16:53-71.

Interpretive Summary: Identifying proteins that are involved in lint/fiber production on the cottonseed has been elusive. This information is vital to developing strategies which incorporate DNA techniques to target improvement in fiber quantity and quality. Numerous reports indicate that cotton lint production may share some regulatory proteins which are involved in developing leaf hairs (trichomes). In this study we examine how leaf hairs develop and survey 29 different cotton lines. Data indicate that two different “mechanics” exist for controlling leaf trichome growth. Cotton is closely related to a “model plant” (Arabidopsis) where over 40 proteins have been discovered to be involved in trichome development. This gives the cotton researcher a list of genes to check which may be shared between Arabidopsis and cotton leaf and ovular lint. Discovery of specific regulatory proteins will allow cotton researchers to understand the protein function and regulation and to develop improvement strategies allowing the U.S.A. to stay competitive in cotton production with foreign countries.

Technical Abstract: This study evaluated and quantified trichome diversity on various cotton lines. Leaf trichomes were evaluated with scanning electron and light microscopy on fixed and live samples. Observations indicated that trichome complexity and quantity increased on the mainstem leaves as sampling progressed up the plant. Glandular trichomes (GTs), however, were found on all leaves examined and were not affected by various loci which either increased or decreased non-GTs (NGTs). Both the GTs and NGTs on cotton leaves were not affected by the expression of N1N1 allele which removed approximately 3/4 of all lint and 100% of all fuzz on cotton ovules. The abaxial side of the leaf usually had more GTs and NGTs. These data indicated at least two mechanisms exist for trichome initiation in cotton leaves, one for GTs and the other for NGTs. Four cotton lines were selected for further genetic characterizations in hopes of identifying genetic linkages to cotton fibers on the seed.